1. Field of the Invention
This invention relates to optical systems, and more specifically, to an optical system incorporating a resonator to enhance the resolution of optical inspection systems and other optical devices.
2. Description of the Related Art
Optical measurement systems, optical storage and retrieval systems and other optical systems may be limited by many factors, including effective detector and illumination resolution. The effective resolution of a detection system is often set by the diffraction limitations of the system. The above-incorporated patent applications disclose techniques for enhancing the performance of a variety of optical systems and improving the resolution of optical technologies disclosed therein.
While incorporation of a resonator within an optical system can provide an improved resolution due to reduction in illumination beam size and/or detection sensitivity of the system, there are limitations on the resolution improvement that may be obtained due to divergence and losses at each internal reflection. If perfectly perpendicular-to-mirror multiple reflections existed in the resonator to support the resonance condition, the resonator would be ideal. However, due to the finite non-zero propagation distance within the resonator caused by microscopic surface variation on the mirrors, as well as by diffraction effects, the internal reflections will deviate from the ideal resonator geometrical optics model of both linear and perpendicular propagation between the mirrors.
It would therefore be desirable to improve the performance of the resonator-enhanced optical systems disclosed in the above-referenced patent applications, as well as other optical systems, in order to further improve their resolution and performance.